Setting Precision in SQL Query

I have a calculated field in a SQL query that sometimes ends up in running decimal fields for more than 15 decimal places. I want to evenly truncate it to 6 decimal places for all records. Please let me know the command in SQL to do so.

Thanks

If it is SQL Server you can use CAST or CONVERT functions

select CONVERT(decimal(25,6),yourvariable)
from yourtable

or

select CAST(yourvariable as decimal(25,6))
from yourtable